The B-Type Natriuretic Peptide (BNP) Test measures BNP levels in blood to help diagnose and monitor heart failure and other cardiac conditions. High levels suggest the heart is under stress, often from congestive heart failure, hypertension, or heart disease. Doctors order this test for patients with shortness of breath, fatigue, or swelling. Results provide critical insight into heart function, guiding treatment and monitoring response to therapy.